DrFord Wants to Test the Hypothesis That Room Color Can

 Dr.Ford wants to test the hypothesis that room color can affect memory.To that end,he randomly assigns 10 students to a condition where they study a written passage while seated in a room that is painted a lilac color.The other 10 students study the passage while seated in an identical room that is painted bright orange.After both groups studied the passage for one hour,they are given a multiple-choice test over the material.Dr.Ford then calculates how many questions the students in both groups answer correctly.In Dr.Ford's study,a potential confounding variable is the ____. 

A) students' test scores
B) color of the room in which the students studied the passage
C) age of the students
D) random assignment to groups